Numerous exercise methods and machines have been developed over the years for strengthening and rehabilitating damaged muscle tissue as well as developing desired muscle tissue. In general, these machines and methods operate on a resistance to movement theory but are limited to those motions which are normally attributed to the particular part of the anatomy, as for example, the normal flexure of the leg or arm. It has been demonstrated, however, that rehabilitation from some injuries and in particular those of a joint require an exercise fostering development and/or strengthening of muscles which are normally little used or used only in particular situations involving unusual movement.
In particular, with respect to the knee, following an injury the party may continue to suffer from a weakened joint condition until those muscles and interconnecting fibers which control lateral and medical movement are strengthened. Obviously, the normal flexing of the leg and foot in a known exercise program will increase the strength of the thigh, calf and other muscles which control the normal flexing movement, i.e., walking, running, and the like. However, those muscles which assist the joint structure in preventing lateral or sideways motion of the joint are not substantially affected by the normal exercise methods or machinery. A careful study of the anatomy of the knee joint reveals a very complex structure; the movement in any direction requires the sliding and relative motion of many separate but interrelated parts.
Prior art devices known to the present inventor include the exercise apparatus disclosed in U.S. Pat. No. 2,668,709 granted Feb. 9, 1954, to Bokyo. This disclosure includes a bicycle pedal-like device for exercising and strengthening the legs in their normal flexing motion and includes as an integral part thereof a manually adjustable brake for controlling the amount of energy necessary to turn the cranks.
Further, U.S. Pat. No. 3,451,674 granted June 24, 1969, to Lundgren, et al, discloses another bicycle-type exercise machine utilizing a standard crank mechanism for exercising the flexure muscles wherein a brake operating in response to centrifugal force increases the resistance to movement as the speed of the device increases.
With the above-noted prior art and background in mind, it is an object of the present invention to provide an exercise machine particularly utilized to increase the strength of those muscles which contribute to the lateral and medial stability of a joint.
It is another object of the present invention to provide an exercise machine which is simple and yet provides a means for increasing the resistance to movement as the strength and ability of the user increases.
Still another object of the present invention is to provide a machine including a display device wherein the user can readily determine the relative amount of resistance and therefore the amount of exercise being performed, thereby being able to regulate and control his progress.
Yet another object of the present invention is to provide an exercise machine primarily for use from a standing position. The particular structure of the machine is such that the user is actively involved and yet the exercise to the critical part of the body i.e., the knee, is to a large measure isometric.
A still further object of the present invention is to provide an exercise machine which because of its configuration and the particular posture of the operator exercises a large percentage of the body ancillary to the main purpose.